1. Field of the Invention
The present invention relates to navigation apparatuses and, more specifically, to navigation apparatuses for guiding a user to a destination through the use of cartographic data.
2. Description of the Background Art
Described below are first and second background arts relating to the present invention, and also their problems.
Navigation apparatuses of a general type usually have the function of guiding a user along a route found to be optimum from a predetermined position to a user-defined destination.
Such a guidance function has recently been improved, i.e., several route options are to be found between departure point and destination which are both user-definable, and the user selects one route out of those. Along the selected route, the navigation apparatuses guide the user toward the destination.
As such, the user""s preferences are taken into consideration at the time of route selection. In this sense, such an improvement has contributed the guidance function to be more user-friendly.
The guidance function after improvement, however, poses the problem of requiring the user to operate the input device of a navigation apparatus to select one route from several others. In the case where a large number of routes are searched and found, the user has to operate the input device again and again until he/she eventually selects one. As such, route selection under the improved guidance function requires the user cumbersome operation.
Some navigation apparatuses also have the function of re-routing, with which route search is performed, if the user""s vehicle goes off the originally-found route, to newly find any other route toward the destination from the user"" position at that time (current position). With such a re-routing function, detour options are to be offered to the user when there occurs any traffic accident, traffic jam, or the like, on the originally-found route.
The problem here is that the conventional re-routing function is not activated unless the user goes off the originally-found route. The user thus has no way of knowing before going off the route whether he/she can avoid traffic accidents and jams on the way ahead with ease. If the worst happens, the user may find the detour option at hand takes him/her much longer to reach the destination.
There is another problem with the conventional re-routing function, that is, provided to the user is only one detour option. Consequently, the user""s preferences or actual traffic conditions are not appropriately reflected in the detour route. More specifically, users have their own preferences, and some may want to go along major roads if possible at all, or reaching the destination as soon as possible may be of their high priority. As such, offering only one detour option under the conventional re-routing function is not sufficient to meet the users"" varying preferences.
Moreover, after taking the offered detour route, the user may find it also jammed. If so, with the conventional re-routing function offering only one detour option, the user has is to go off the detour route to have any other alternative route. The conventional re-routing function is not thus helpful enough for the user to find detour routes as traffic conditions demand.
Therefore, an object of the present invention is to provide navigation apparatuses capable of automatically selecting one route from several others derived through route search.
Another object of the present invention is to provide navigation apparatuses capable of offering a user, before going off the originally-found route, several other route options.
The present invention has the following features to attain the objects above.
A first aspect of the present invention is directed to a navigation apparatus for guiding a user to a destination through the use of cartographic data. The navigation apparatus comprises: a route search section for searching for a plurality of routes from a starting point to one or more of destinations by using the cartographic data, and generating route data for each of the found routes; a movement information generation section for generating movement information which relates to the user""s movement; a selection section for selecting, based on the movement information generated by the movement information generation section, one of the route data plurally generated by the route selection section; a guidance data generation section for generating, based on the route data selected by the selection section and the cartographic data, guidance data for guiding the user to the corresponding destination; and an output section for outputting an image or a sound for guiding the user toward the destination in accordance with the guidance data generated by the guidance information generation section.
A second aspect of the present invention is directed to a navigation apparatus for guiding a user to a destination through the use of cartographic data. The navigation apparatus comprises: a route search section for searching for a first route from a departure point toward the destination by using the cartographic data; a guidance data generation section for generating guidance data for guiding the user toward the destination based on the first route found by the route search section and the cartographic data; and an output section for outputting the guidance data generated by the guidance information generation section. When a predetermined starting condition is satisfied during when the guidance data is being outputted, the route search section further searches for a plurality of second routes from the user""s current position toward the destination. The navigation apparatus further includes a warning data generation section to generate warning data for notifying the user of the plurality of second routes found by the route search section. The warning data thus generated by the warning data generation section is also outputted from the output section. Here, the plurality of second routes are varying in course on the way from the user""s current position to the same destination as the first route, and should not coincide with the first route.